English
For every a on the unit circle and every real x, the sine kernel is odd in its first argument: sinKernel(-a, x) = - sinKernel(a, x).
Русский
Для каждого a на единичном круге и любого действительного x син Kernel нечетна по первому аргументу: sinKernel(-a, x) = - sinKernel(a, x).
LaTeX
$$$\\sinKernel(-a, x) = -\\sinKernel(a, x). $$$
Lean4
theorem sinKernel_neg (a : UnitAddCircle) (x : ℝ) : sinKernel (-a) x = -sinKernel a x := by
induction a using QuotientAddGroup.induction_on with
| H a => simp [← ofReal_inj, ← QuotientAddGroup.mk_neg, sinKernel_def, jacobiTheta₂'_neg_left, neg_div]